Koh uses two-dimensional photography to create holographic, three-dimensional constructions. His photo sculpture has a transparent surface that reflects the images of the world, and yet reveals the emptiness of its interior space. The overlapping planes create an illusion of indefinable depth and varying imagery, depending on the viewing angle. Stairway-13 shows a transparent building with a blue stairway. The photographic image of a building collides with that of a sea wave to form the surreal surface of a fantasy building. The photograph was taken in New York.